This invention relates to a data processing circuit and can be applied suitably, for example, to a recording and reproduction apparatus for recording and reproducing music data and particularly to a data processing circuit provided in a data processing apparatus such as a personal computer and a music reproduction apparatus.
A conventional disk reproduction apparatus includes a system controller for controlling the entire disk reproduction apparatus such that music data (hereinafter referred to as compressed music data) compression coded in advance and recorded on a magneto-optical disk are read out at a first rate for each predetermined recording unit and also address data of such compressed music data for each recording unit (hereinafter referred to as recording unit compressed music data) on the magneto-optical disk is read out. Then, the disk reproduction apparatus temporarily and cumulatively stores the recording unit compressed music data successively read out from the magneto-optical disk in this manner in a coordinated relationship with the address data into a RAM (Random Access Memory) serving as a buffer memory.
Further, the disk reproduction apparatus successively reads out the recording unit compressed music data at a second rate lower than the first rate from the RAM and decompresses the read out compressed music data by means of a data decompression circuit. Then, the disk reproduction apparatus converts music data obtained by the decompression from digital data into an analog signal and signals the analog signal to a headphone or the like. Consequently, even if it is temporarily rendered difficult to read out the recording unit compressed music data from the magneto-optical disk by vibration of the disk reproduction apparatus applied from the outside, the disk reproduction apparatus can continue to successively read out the recording unit compressed music data cumulatively stored in the RAM from the RAM for a period of time until reading out of the recording unit compressed music data is re-started. Accordingly, such a disk reproduction apparatus as described above prevents intermittent interruption of sound of the music outputted from the headphone or the like when the recording unit compressed music data are read out from a magneto-optical disk and processed for reproduction. A disk reproduction apparatus of the type described is disclosed, for example, in Japanese Patent Laid-Open No. Hei 6-150540 (pages 2 and 4 and FIG. 3, hereinafter referred to as Patent Document 1).